Supplementary Table 1: The sentinel hospital IDs and locations. There are 23 hospital sites that perform laboratory confirmation of V. cholerae in Bangladesh.
| ID | Hospital | Division | Type |
|---|---|---|---|
| 1 | District Hospital Norshingdi | Dhaka | district |
| 2 | Adhunik Sadar Hospital Habiganj | Sylhet | district |
| 3 | District Sadar Hospital Cox’s Bazar | Chittagong | district |
| 4 | Adhunik Sadar Hospital Naogaon | Rajshahi | district |
| 5 | General Hospital Patuakhali | Barisal | tertiary |
| 6 | Adhunik Sadar Hospital Thakurgaon | Rangpur | district |
| 7 | District Sadar Hospital Satkhira | Khulna | district |
| 8 | Dhaka Medical College Dhaka | Dhaka | tertiary |
| 9 | Uttara Adhunik Medical College Hospital | Dhaka | tertiary |
| 10 | Bangladesh Institute of Tropical and Infectious Diseases Chittagong | Chittagong | tertiary |
| 11 | General Hospital Tangail | Dhaka | district |
| 12 | General Hospital Narayanganj | Dhaka | district |
| 13 | Sadar Hospital Chuadanga | Khulna | district |
| 14 | General Hospital Meherpur | Khulna | district |
| 15 | General Hospital Comilla | Chittagong | district |
| 16 | Upazila Health Complex Chaugachha Jesssore | Khulna | subdistrict |
| 17 | General Hospital Kusthia | Khulna | district |
| 18 | Upazila Health Complex Madan | Mymensingh | subdistrict |
| 19 | Upazila Health Complex Chhatak Sunamganj | Sylhet | subdistrict |
| 20 | Upazila Health Complex Mathbariya | Barisal | subdistrict |
| 21 | Upazila Health Complex Bakerganj | Barisal | subdistrict |
| 22 | Health Complex Shibganj | Rajshahi | subdistrict |
| 23 | icddr,b Cholera Hospital | Dhaka | icddrb |
Supplementary Table 2: Population living in the cholera surveillance zone.
| Buffer (Subdistrict-District-Tertiary-icddr,b in km) | Pop | Proportion |
|---|---|---|
| 10-20-30-30 | 50888584 | 0.3129697 |
Supplementary Figure 1: A. Median risk of V. cholerae seroincidence relative to a population-weighted mean by 5 km x 5 km grid cell. These relative risk estimates are bounded such that RRs above and below 2 and -2 were plotted as the values 2 and -2, respectively. The black marks indicate sentinel hospital locations. B. Median number of estimated V. cholerae infections per grid cell in the previous year. The black marks indicate sentinel hospital locations. These estimates were calculated as the product of the median seroincidence risk and 2015 WorldPop population estimate in each grid cell. The black marks indicate sentinel hospital locations.
Figure 1: Cholera greyspots. The 5 km x 5 km grid cells that are colored are cells covered in the cholera surveillance zone. The greyed out grid cells are areas not captured by the national cholera surveillance system in Bangladesh, where we have little information on clinical cases of cholera.
Figure 2: A. Cholera risk map as categorized by the risk of seroincidence relative to a population-weighted mean by 5 km x 5 km grid cell. The map illustrates grid cells of High-Considerate-Moderate risk and the which grid cells are captured by the cholera surveillance zone (10-20-30-30km for subdistrict, district, and tertiary care, and icddr,b hospitals), indicated by the transparent buffers. B. Cholera risk map as categorized by the estimated number of V. cholerae infections by 5 km x 5 km grid cell. The black marks indicate sentinel hospital locations and the transparent buffers overlayed represent the cholera surveillance zone.
Figure 3: A. Bar plot of the number of people (above x-axis) and number of infections (below x-axis) in the Bangladesh population and in the cholera surveillance zone living in high-considerable-moderate risk areas as defined by relative seroincidence risk and absolute number of infections risk measures. B. Bar plot of the percentage of the population (above x-axis) and percentage of infections (below x-axis) in Bangladesh and the cholera surveillance zone living in high-considerable-moderate risk areas using the relative seroincidence risk and absolute number of infections as measures of risk.
Supplementary Figure 3:
Supplementary Table 3: Population living in each risk category. The population living in high, moderate, and low risk areas according to relative seroincidence risk and absolute risk across Bangladesh. The risk categories are defined by the 25th and 75th percentiles of the relative risk or number of infections in each grid cell.
| Risk Level | Population | Risk Measure |
|---|---|---|
| High | 35885510 | Relative Risk |
| Considerable | 64914640 | Relative Risk |
| Moderate | 61798921 | Relative Risk |
| High | 89111436 | Absolute Risk |
| Considerable | 68300021 | Absolute Risk |
| Moderate | 5187614 | Absolute Risk |
Table 1: The population not captured in the surveillance greyspots (cholera surveillance zone).
| Greyspot type | Greyspot population | Percent in greyspot |
|---|---|---|
| Surveillance greyspot | 111,710,486 | 68.7 |
Table 2: Part 1. Number and percent infections that may be captured in cholera surveillance zones. The percent infected represents the percentage of infected individuals captured within the cholera surveillance zone out of all infected individuals in Bangladesh. Part 2. Number and percent infections that may be captured in cholera surveillance zones, categorized by relative risk and absolute risk. The infections in surveillance zone represents the percentage of infected people in high-considerable-moderate risk grid cells among all infections within the cholera surveillance zone. The population in surveillance zone represents the percentage of people living in high-considerable-moderate risk grid cells among all people within the cholera surveillance zone. The distribution should across risk categories should sum to 100% for each set of buffer sizes. Part 3. Number and percent infections that may be captured in Bangladesh, categorized by relative risk and absolute risk. The captured at-risk population represents the percentage of high-moderate-low risk populations captured by the cholera surveillance zone out of all high-considerable-moderate risk populations in Bangladesh. The captured infections represents the percentage of infections in high-moderate-low risk grid cells among all infections in high-considerable-moderate risk grid cells across Bangladesh.
| Buffer size | Surv. zone pop | Number infected | % infected in surv. zone pop | % of all BGD infections |
|---|---|---|---|---|
| 10-20-30-30km | 50888584 | 8,005,303 ( 4,588,667 , 11,886,760 ) | 15.7322 ( 13.3 , 23.4 ) | 28.5276 ( 26.6 , 34.6025 ) |
| Buffer size | Risk Measure | Risk category | Number infected | % surv. zone infections | Surv. zone pop | % BGD pop in surv. zone |
|---|---|---|---|---|---|---|
| 10-20-30-30km | Absolute Risk | High | 6,161,714 ( 3,464,602 , 9,159,009 ) | 76.9664 ( 74.2 , 85.9 ) | 32,815,402 ( 27,464,930 , 36,813,855 ) | 64.4848 ( 61.6 , 72.3025 ) |
| 10-20-30-30km | Absolute Risk | Considerable | 1,781,751 ( 758,604.3 , 2,775,329 ) | 22.262 ( 19.6 , 30.6 ) | 16,540,234 ( 13,284,654 , 20,448,577 ) | 32.5042 ( 29.8 , 40.2025 ) |
| 10-20-30-30km | Absolute Risk | Moderate | 61,838.36 ( 21,388.8 , 114,633.3 ) | .7709 ( .6 , 1.3 ) | 1,532,948 ( 537,929.3 , 3,589,343 ) | 3.0118 ( 1.9 , 7.1 ) |
| 10-20-30-30km | Relative Risk | High | 3,434,680 ( 1,800,494 , 6,016,285 ) | 43.3947 ( 36.5 , 65 ) | 10,060,550 ( 5,614,175 , 16,447,115 ) | 19.7712 ( 16 , 32.3025 ) |
| 10-20-30-30km | Relative Risk | Considerable | 3,583,606 ( 1,602,120 , 6,026,203 ) | 44.4108 ( 39.4 , 58.5 ) | 23,900,262 ( 16,973,965 , 31,466,839 ) | 46.966 ( 41.275 , 61.8 ) |
| 10-20-30-30km | Relative Risk | Moderate | 987,017.5 ( 218,968.8 , 2,435,070 ) | 12.1946 ( 7.975 , 26.4025 ) | 16,927,772 ( 8,459,092 , 26,323,286 ) | 33.264 ( 26.4 , 51.7025 ) |
| Buffer size | Risk Measure | Risk category | Surv. zone pop | Surv. zone infections | Captured At-Risk Pop (%) | Captured Infections (%) |
|---|---|---|---|---|---|---|
| 10-20-30-30km | Absolute Risk | High | 32,815,402 ( 27,464,929 , 36,813,855 ) | 6,161,714 ( 3,464,601 , 9,159,009 ) | 41.8975 ( 40.6 , 45.8025 ) | 33.3241 ( 30.1 , 42.3025 ) |
| 10-20-30-30km | Absolute Risk | Considerable | 16,540,234 ( 13,284,654 , 20,448,578 ) | 1,781,751 ( 758,604.4 , 2,775,329 ) | 22.025 ( 20.5 , 26.5025 ) | 19.8105 ( 19 , 22.1 ) |
| 10-20-30-30km | Absolute Risk | Moderate | 1,532,948 ( 537,929.5 , 3,589,343 ) | 61,838.36 ( 21,388.71 , 114,633.8 ) | 15.7958 ( 11.5 , 27.8025 ) | 10.7625 ( 9.1 , 15.5025 ) |
| 10-20-30-30km | Relative Risk | High | 10,060,550 ( 5,614,175 , 16,447,115 ) | 3,434,680 ( 1,800,494 , 6,016,284 ) | 26.3327 ( 22.4 , 38.1025 ) | 25.8756 ( 21.6 , 39.0025 ) |
| 10-20-30-30km | Relative Risk | Considerable | 23,900,262 ( 16,973,965 , 31,466,840 ) | 3,583,606 ( 1,602,120 , 6,026,202 ) | 30.0859 ( 27.5 , 36.7 ) | 29.6678 ( 27 , 36.8 ) |
| 10-20-30-30km | Relative Risk | Moderate | 16,927,772 ( 8,459,092 , 26,323,286 ) | 987,017.5 ( 218,968.5 , 2,435,070 ) | 36.5226 ( 31.875 , 49.0025 ) | 35.6702 ( 31.6 , 47 ) |